The present invention generally relates to a dielectric resonator with an earth electrode and a resonance electrode being formed on a dielectric base plate or a dielectric block, and a manufacturing method thereof.
A dielectric resonator having resonance electrodes (internal conductors) formed within a dielectric block, and earth electrodes (external conductors) formed on the outside face of a dielectric block is known. Also known is a dielectric resonator having resonance electrodes (strip lines) formed on one surface of a dielectric base plate and earth electrodes formed on an opposite surface. Such resonators are used as filters and so on in, for example, microwave frequency bands.
Coils for connecting resonators, capacitors and base plates and so on for mounting them, together with a plurality of dielectric resonators, capacitors and base plates and so on are accommodated within a case in a dielectric filter of a discrete type which includes, for example, a plurality of dielectric resonators.
Various types of dielectric resonators, coils and capacitors are used in accordance with the required specifications in the dielectric filters of such construction.
In an integrated type of dielectric filter, a plurality of resonators are constructed on a dielectric block which is integral from the beginning, or which is integrated by the assembling operation, and correspond to a plurality of stages of dielectric filters and so on.
A transmission filter and a reception filter are used in a transceiver sharing device in, for example, the microwave,band. Characteristics such as a smaller damping amount in the transmission band and yet a sufficiently large damping amount in the transmission band are required in the reception filters. It is effective to provide a pole (hereinafter referred to as polarization) as an effective method in the designing of a band pass filter capable of having a given damping amount in a frequency zone generally away from the pass band width.
In the dielectric filter of the conventional construction, it is not suitable for a dielectric filter to be of a type which mounts on the surface of, for example, a base plate, because the terminal for coupling use has to be inserted from the outside into the resonance electrode formed hole so as to interconnect the resonators of the given stages. Also, special parts are required for the operation in order to directly effect the electromagnetic connection among its front, rear resonators with the resonator of one or more stages being bypassed.
A dielectric resonator of a surface mounting type as shown in FIG. 65 and FIG. 66 is taken into consideration in connection with the present application and has been disclosed in Japanese Patent Laid-Open Publication No. 3-303366.
FIG. 65 is a perspective view of a dielectric resonator. FIG. 66 is a top face view of the dielectric resonator. In FIG. 65, reference numerals 102, 103 are respectively dielectric base plates. Sectional semi-circular shaped grooves 105, 106, 107, 108, 109 are provided respectively on a first main face (a face opposite to the dielectric base plate 103) of the dielectric base plate 102 and the first main face (a face opposite to the dielectric base plate 102) of the dielectric base plate 103, with internal conductors being respectively formed on the inside faces thereof. Signal input, output electrodes (115) are formed across the second main face (bottom face in the drawing) from two side faces of the dielectric base plates 103. Coupling electrodes E10 are formed on a given region of the second main face (top face in the drawing) of the dielectric base plate 102. An external conductor 112 is formed on the external surfaces of the dielectric base plates 102, 103 except for the regions of the above described signal input, output electrodes (115) and the coupling electrodes E10. As shown in FIG. 66, the coupling electrodes E10 effect the respective capacity connection between the open end vicinity of the internal conductors 117, 119 within the internal formed holes 106, 108 as shown in FIG. 65. By such construction, the second stage and the fourth stage among the band pass filters of five stages are interconnected so as to cause the damping pole on the low-pass side of the pass band width.
The dielectric resonators shown in FIG. 65 and FIG. 66 can be provided with poles without addition of special parts, with a large operational advantage, in that the surface mounting operation can be effected on the circuit base plate together with the electronic parts of the other surface mounting type. However, in such conventional dielectric filter as shown in FIG. 65 and FIG. 66, the Qo value of the resonator is lower, thus resulting in a danger of deteriorating the insertion loss characteristics of the filter, because the current flowing through the external conductor 112 is interrupted in the region where the coupling electrode E10 is formed. As the coupling electrode formed region becomes an open portion of the external conductor, some electromagnetic field leakage is caused, so that the influence of a metallic unit adjacent to the dielectric filter may become a problem.
In a dielectric filter of the conventional discrete type, individual parts such as coils, capacitors or the like are required together with a plurality of dielectric resonators, with a defect that the whole becomes larger in size as the number of the parts increases, and the assembling operation step is complicated. In the conventional integral type of dielectric filter, only the filter of the characteristics restricted is provided in the pattern formation of the resonance electrode or the earth electrode although the above described defects are not provided. When the plan circuit and so on are constructed with one portion of the earth electrode (external conductors) being patterned, some measures are required to be taken with respect to the electromagnetic leakage.
Also, in the conventional dielectric filter, there is danger of lowering the Qo value of the resonator, deteriorating the insertion loss characteristics of the filter, because the current flowing through the external conductor is interrupted in the region of the coupling electrode. As the coupling electrode region is an opening portion of the external conductor, there is danger of causing some electromagnetic leakage, which causes a problem of influence by the metallic unit adjacent to the dielectric filter.
In the conventional dielectric filter, the respective base plate, capacitor element and coil parts are necessary and further, a soldering operation for engaging the respective parts is required, which causes the problems that the cost rises and also, the productivity is lower.
Further, since the pole-providing electrode is formed within the region of the earth electrode with one portion of the earth electrode of the dielectric base plate being shaved off to form the conventional polarized construction, the earth current flowing through the above described earth electrode is interrupted in the above described gap portion, which causes a problem that the Qo value of the resonance electrode is deteriorated, and the characteristics of insertion loss are lowered.
Accordingly, a primary object of the present invention is to provide a dielectric resonator which basically assumes the construction of an integral type dielectric resonator and is smaller in size and can easily obtain specific given characteristics.
Another object of the present invention is to provide a dielectric resonator which is capable of effecting polarization without addition of special parts.
Still another object of the present invention is to provide a dielectric resonator which is suitable for use in a polarized dielectric filter superior in the insertion loss characteristic without loss of Qo value of the resonator;
A further object of the present invention is to provide a dielectric filter which has a reduced number of parts and a reduced cost, and can improve productivity by omitting manufacturing steps.
A still further object of the present invention is to provide a dielectric filter which can avoid the deterioration of the Qo value, when the pole-providing electrode is added, to improve the insertion loss.
A dielectric resonator of a first embodiment of the invention is composed of additional electrode layers within the above described dielectric in a dielectric resonator where a plurality of resonance electrodes are arranged, and a dielectric is interposed between the resonance electrodes and the additional electrodes.
In the dielectric of the first embodiment of the invention, a plurality of resonance electrodes and earth electrodes are formed, separated by dielectrics and also, additional electrode layers are provided within the dielectric. The additional electrode layers function as electrodes to be connected with, for example, the resonance electrodes, electrodes for constituting inductor, capacitor, line and so on or a plan circuit including them, and constitute various types of filters and so on such as BPF, BEF, LPF, HPF or the like together with a plurality of resonators.
A dielectric resonator in accordance with a second embodiment of the invention has a coupling electrode layer provided for effecting capacity connection with a plurality of resonance electrodes within the above described dielectric, in a dielectric resonator where a plurality of resonance electrodes are arranged, dielectrics are interposed among these resonance electrodes and the earth electrodes.
In the dielectric resonator of the second embodiment of the invention, a plurality of resonance electrodes and earth electrodes are formed through dielectrics, and also, coupling electrode layers are provided within the dielectric. The coupling electrode layer is connected by capacity with a plurality of resonance electrodes. In a band pass filter of, for example, three stages or more, a damping pole is formed on the high-pass side of the pass band by the capacity connection through a coupling electrode layer between first, second stages of resonance electrodes. If the capacity connection is effected through the coupling electrode layer between the resonance electrodes of second and fourth stages of resonance electrodes among, for example, five stages of band passing filter, a damping pole is formed on theand low-pass side of the pass band.
The additional electrode layer is provided within the dielectric. The coupling electrode is not required to be provided within the earth electrode formed region. Current flowing through the earth electrodes is not interrupted. The Qo value is not lowered. The filter can be used as a dielectric filter of less insertion loss.
A third embodiment of the invention is a dielectric filter characterized in that an earth electrode is formed on the other main face of the dielectric base plate, a plurality of resonance electrodes are formed on one main face, and one side face of the resonance electrode is connected with the above described earth electrode so as to have a coupling electrode, a stray electrode and a coil electrode pattern-formed within the above described dielectric basic plate.
In order to form the respective electrodes within the above described dielectric base plate, the portion facing the resonance electrode of the dielectric base plate is cut into two divisions, and the respective electrodes are formed in pattern by, for example, a screen printing method on one of the divided cut faces so as to stick to both of them.
When the resonance electrode is formed on the above described dielectric base plate, both are connected with each other if adjacent resonance electrodes are brought too close, so that the desired characteristics may be not be obtained. In order to avoid the connection of the resonance electrodes, a removing operation can be effected by the interval between the resonance electrodes. The size of the dielectric base plate becomes larger correspondingly by the interval of both the electrodes, thus causing a disadvantage that the whole part becomes larger in size.
According to the dielectric filter of the third embodiment of the invention, the coupling electrode, the stray electrode and the coil electrode are formed in pattern within the dielectric base plate, and the respective electrodes can be formed at the same time. The number of the parts can be reduced as compared with a case where a base plate is disposed on the conventional dielectric coaxial resonator, the parts such as capacitor element, coil and so on are connected with the base plate, and the cost can be lowered, thus improving productivity.
A fourth embodiment of the invention is characterized in that the shielding electrode is formed between the adjacent resonance electrodes on one main face of the above described dielectric base plate, and both the ends of the shielding electrode are connected with the above described earth electrodes.
In the fourth embodiment of the invention, the shielding electrode connected with the earth electrode is formed between the resonance electrodes of the above described dielectric base plate. As the electric force lines to be emitted from both the above described resonance electrodes are absorbed by the shielding electrodes, the intervals between the resonance electrodes can be narrowed without deterioration in the characteristics, and the dielectric base plate can be made correspondingly smaller in size.
A fifth embodiment of the invention is characterized in that the above described polarized electrode is formed within the above described dielectric base plate, in the pole-providing construction of a dielectric filter where a plurality of resonance electrodes are formed on one main face of the dielectric base plate, and an earth electrode is formed on the other main face, one side face of the above described resonance electrode is connected with the earth electrode, a pole-providing electrode for connecting by capacity the above described resonance electrode with the above described dielectric base plate is formed.
In order to form the pole-providing electrode within the above described dielectric base plate, a portion facing the resonance electrode of the above described dielectric base plate is cut so as to have the base plate formed into two divisions, the pole-providing electrode is formed on the cut face of one side of the divided form so as to stick to both of them.
According to the dielectric filter of the fifth embodiment of the invention, the pole-providing electrode is formed within the dielectric base plate. As the earth electrode can be formed on the full face of the other main face of the dielectric base plate, the obstruction of the electric current in the formation of the pole-providing electrode by shaving the conventional earth electrode can be removed. As a result, the reduction in the insertion loss can be improved by the avoidance of the deterioration in the Qo value, thus improving the electric characteristics.
A method of manufacturing a dielectric resonator of a sixth embodiment of the invention comprises the steps of connecting a dielectric base plate with a plurality of resonance electrode films being formed on it with a plurality of base plates including a dielectric base plate with additional electrode films being formed on it, manufacturing a dielectric resonator having the additional electrode layers within the dielectric.
In a method of manufacturing the dielectric resonator of the sixth embodiment of the invention, the dielectric resonator having the additional electrode layers within the dielectric is manufactured by the connection of a dielectric base plate with a plurality of resonance electrode films being formed on it with a plurality of base plates including dielectric base plate with additional electrode films being formed on it.
Therefore, the additional electrode layers to be provided within the dielectric has only to be formed in advance on the dielectric base surface.
A method of manufacturing a dielectric resonator of a seventh embodiment of the invention comprises the steps of connecting a dielectric base plate with a plurality of resonance electrode films and additional electrode films being formed on it opposite to the these resonance electrode films, with a plurality of base plates including the other dielectric base plate, manufacturing a dielectric resonator having additional electrode layers in the dielectric interior.
In a method of manufacturing the dielectric resonator of the seventh embodiment of the invention, a plurality of resonance electrode films and additional electrode films opposite to these resonance electrode films are formed on a certain one dielectric base plate, and the other base plate is connected on the base plate.
A method of manufacturing a dielectric resonator of an eighth embodiment of the invention comprises the steps of composing a dielectric unit having a plurality of resonance electrode films formed therein, connecting a dielectric base plate with the additional electrode films being formed on it with the above described dielectric unit, manufacturing a dielectric resonator having additional electrode layers within the dielectric.
In a method of manufacturing the dielectric resonator of the eighth embodiment of the invention, the dielectric base plate with additional electrode films being formed on it is connected with respect to the dielectric unit with a plurality of resonance electrode dielectric films being formed therein. In this case, the dielectric unit constitutes a plurality of dielectric resonators, and a plane circuit is added with respect to a plurality of dielectric resonators by the connection the dielectric base plates having the additional electrode films.
A method of manufacturing a dielectric resonator of a ninth embodiment of the invention comprises the steps of using a dielectric ceramic green sheet with a plurality of resonance electrode films being formed on it, a dielectric ceramic green sheet with additional electrode films being formed on it, effecting an integral laminated confirming operation, manufacturing a dielectric resonator having additional electrode layers within the dielectric.
In the method of manufacturing the dielectric resonator of the ninth embodiment of the invention, the dielectric ceramic green sheet with a plurality of resonance electrode films being formed on it, the dielectric ceramic green sheet with additional electrode films being formed on it are cofired integrally in lamination. Therefore, the additional electrode films are formed on the dielectric ceramic green sheet in this case, and the additional electrode layers are constructed within the dielectric by the subsequent integral cofiring operation.
A method of manufacturing a dielectric resonator of a tenth embodiment of the invention comprises the steps of connecting a dielectric base plate with a plurality of resonance electrode films being formed on it with a plurality of base plates including a dielectric base plate with a coupling electrode film being formed on it, manufacturing a dielectric resonator having coupling electrode layers within the dielectric.
In a method of manufacturing a dielectric resonator of the tenth embodiment of the invention, a dielectric base plate with a plurality of resonator electrode films being formed on it is connected with a plurality of base plates including a dielectric base plate with coupling electrode films being formed on it so that a dielectric resonator having coupling electrode layers within the dielectric is manufactured. Therefore, coupling electrode layers to be provided within the dielectric have only to be formed on the dielectric base surface in advance.
A method of manufacturing a dielectric resonator of an eleventh embodiment of the invention comprises the steps of connecting a dielectric base plate with a plurality of resonance electrode films and coupling electrode films being formed opposite to these resonance electrode films with a plurality of base plates of the other dielectric base plate, manufacturing a dielectric resonator having the coupling electrode layers within the dielectric.
In a method of manufacturing a dielectric resonator of the eleventh embodiment of the invention, a plurality of resonance electrode films and coupling electrode films opposite to these resonance electrode films are formed on a certain one dielectric base plate, and the other base plate is connected with the base plate.
A method of manufacturing a dielectric resonator of a twelfth embodiment of the invention comprises the steps of constituting a dielectric unit with a plurality of resonance electrode films therein being formed therein, connecting a dielectric base plate with coupling electrode films being formed on it with the above described dielectric unit, manufacturing a dielectric resonator having coupling electrode layers within the dielectric.
In a method of manufacturing the dielectric resonator of the twelfth embodiment of the invention, the dielectric base plate with the coupling electrode films being formed on it is connected with respect to a dielectric unit with a plurality of resonance electrode films being formed therein. it. In this case, the dielectric unit constitutes a plurality of dielectric resonators, coupling electrodes are added with respect to the plurality of dielectric resonators by the connection of the dielectric base plate having the coupling electrode films.